This invention relates to superconducting devices and manufacturing methods for same.
Along with efforts to make integrated circuits more dense, high operational speeds are required. The fine structures of electric circuits give rise to problems of decrease in operational speed and in reliability at exothermic parts of integrated circuits. Because of this, if semiconductor devices are driven at the liquid nitrogen temperature, the mobilities of electron and hole become 3-4 times as faster as those at room temperature and as a result the frequency characteristics can be improved.
An attempt to make use of superconductors for semiconductor devices is described in Japanese Patent Application No.sho62-053724 filed on Mar. 9, 1987 in the name of the assignee of this application. In that application, it has been proposed to make lead lines utilizing superconducting ceramic materials. The superconducting ceramics have to be fired for a long time period in an oxidizing atmosphere after applied on the semiconductor substrate in place. Because of this, some surface portion of the semiconductor tends to be oxidized and form insulating oxide films. For example, in case of silicon semiconductor devices, silicon oxide is formed adjacent to their superconducting electrodes.